Performance evaluation of metakaolin clay geopolymers synthesised with bamboo wood ash as an activator

Global concern about substantial CO2 emissions during manufacturing of Portland cement has led to studies on alternative low cost green binders. Geopolymer, an inorganic binder, which is produced from reaction of an alkaline activator and aluminosilicate mineral is receiving attention as an alternative cementitious material. However, one of the drawbacks of geopolymer production is the cost of chemical activators used in its synthesis. Studies are scanty on the use of Bamboo Wood Ash (BWA) as a less expensive alternative biomass ash activator in the synthesis of metakaolin clay geopolymers. Possibility of replacing a part of the alkaline commercial activator with alkaline-rich biomass ash activator was investigated. Metakaolin clay-based geopolymers were synthesised from kaolin clay obtained from Ikere-Ekiti, Ekiti state, Nigeria and calcined at 700°C for 6 hours. Bamboo wood was obtained as a waste from a construction site in Ibadan, ashed and used as alkaline source in place of NaOH. The chemical composition of BWA and calcined clay were characterised by X-ray fluorescence spectroscopy. Geopolymers with BWA to calcined clay ratios of 5:95, 10:90, 20:80, 30:70 and 40:60 were synthesised with sodium silicate solution. Setting time, compressive strength (at 7, 14, 21 and 28 days), water absorption and density of the geopolymers were determined and compared with 100% clay geopolymers synthesised with the reported 8M NaOH/Na2SiO3 activator. The BWA contained 22.9% K2O. Setting time of geopolymers increased with increasing ash/clay ratio, enhancing ease of handling and workability. At 28 days, the compressive strength values of the geopolymers containing less than 30% BWA are higher than the 28.9 MPa of the reference geopolymer. The 10% BWA:-calcined clay geopolymer exhibited the highest compressive strength (45.5 MPa), followed by 20% BWA geopolymer (38.8 MPa). Water absorption capacity values of BWA-metakolin clay geopolymers are lower than that of the reference geopolymer. Increase in the proportion of BWA resulted in increase in geopolymers bulk density. Bamboo wood ash is proposed as an alkali activator in geopolymer synthesis

Microbial Evaluation of Geophagic and Cosmetic Clays from Southern and Western Nigeria: Potential Natural Nanomaterials

Geophagic and cosmetic clays are among potential nano-material which occur naturally and are of various forms. The use of these nano-clays is a common practice in both rural and urban areas mostly due to tradition and medicinal reasons. These naturally occurring materials can be valuable sources of nano-material by serving as nano-composites. The need to ascertain the safety of these materials is the motivation for this research. Physical Characterization based on the hue value and microbiological qualities of the nano-clays were carried out. The Microbial analysis of the clay samples showed considerable contamination with both bacteria and fungi with fungal contaminants taking the lead. This observation may not be unlikely due to the ability of fungi species to survive harsher growth conditions than bacteria. 'Atike pupa' showed no bacterial growth. The clay with the largest bacterial count was Calabash chalk (Igbanke), while that with the highest fungal count was 'Eko grey'. The most commonly isolated bacteria in this study were Clostridium spp. and Corynebacterium spp. while fungi included Aspergillus spp. These results are an indication of the need to subject these clay materials to treatments such as heating before consumption or topical usage thereby ascertaining their safety

ICT Needs and Skills Requirements for Reference Services in the Post-covid Era.

The paper examined the ICT needs and skills requirement for reference services in the post COVID era. Non-probability judgmental sampling was used to select six (6) reference librarians, two from each of three higher institutions in Ibadan: Kenneth Dike Library, University of Ibadan, University Library, Lead City University and Polytechnic Library, The Polytechnic Ibadan. Data was collected through interview and was analyzed thematically. The results revealed that the basic needs of ICT for reference services are to provide fast and accurate service to patrons, easy access and retrieval of reference material, achieve fast and effective communication between the reference librarian and the users and to facilitate feedback. Additionally, the relevant ICT skills needed for reference services in the post COVID era are word processing skills, computer literacy, mobile technology skills, use of social networking sites, the use scanner, photocopier and printer. Moreover, the study reveals that the ICT skills of the respondents is moderately high and majority of the respondents acquire their skills through trial and error, training and re-training by their colleagues and self-sponsorship. The study also revealed that the relevant ICTs used for reference services such as Word processing, e-mail, instant messaging tools, internet, scanner, printer, photocopier, mobile technology, and social media. The major challenge revealed by this study is inadequate funding which is at the center of all other challenges highlighted in this paper. The study suggests management support for ICT skills training and continuous professional development to improve reference librarians among others

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Comparative Physicochemical and Microbiological Qualities of Source and Stored Household Waters in Some Selected Communities in Southwestern Nigeria

In this study, we evaluated the physicochemical and microbial qualities of source and stored household waters in some communities in Southwestern Nigeria using standard methods. Compared parameters include: physicochemical constituents; Temperature (T), pH, Total Dissolved Solids (TDS), Total Hardness (TH), Biological Oxygen Demand (BOD), Magnesium ion (Mg2+) and Calcium ion (Ca2+) and microbiological parameters included Total Coliform Counts (TC), Faecal Coliform Counts (FC), Fungal Counts (Fung C), Heterotrophic Plate Counts (HPC).Comparing Stored and Source samples, the mean values of some physicochemical parameters of most of the stored water samples significantly (p < 0.05) exceeded that of Sources and ranged in the following order: T (15.3 ± 0.3 °C–28.3 ± 0.5 °C), pH (6.4 ± 0.1–7.6 ± 0.1), TDS (192.1 ± 11.1 ppm–473.7 ± 27.9 ppm), TH (10.6 ± 1.7 mg/L–248.6 ± 18.6 mg/L), BOD (0.5 ± 0.0 mg/L–3.2 ± 0.3 mg/L), Mg2+ (6.5 ± 2.4 mg/L–29.1 ± 3.2 mg/L) and Ca2+ (6.5 ± 2.4 mg/L–51.6 ± 4.4 mg/L). The mean microbial counts obtained from microbial comparison of different points (Stored and Source) of collection showed that most of the stored water had counts significantly exceeding (p < 0.05) those of the source water samples (cfu/100 mL) which ranged as follows: TC (3.1 ± 1.5–156.8 ± 42.9), FC (0.0 ± 0.0–64.3 ± 14.2) and HPC (47.8 ± 12.1–266.1 ± 12.2) across all sampled communities. Also, the predominant isolates recovered from the samples were identified as Escherichia coli, Klebsiella pneumonia, Pseudomonas aeruginosa, Enterobacter aerogenes, Aspergillus spp., Mucor spp., Rhizopus spp. and Candida spp. The presence of these pathogenic and potentially pathogenic organisms in the waters and the high counts of the indicator organisms suggest the waters to be a threat to public health

Omnibus Survey of Student Well-Being

This omnibus survey, developed by 6 researchers, seeks to study student well-being during COVID-19. Topics include student-teacher relationships, feelings of belonging in school, student stress and coping mechanisms, and social media use

Performance of [18F]Flutemetamol Amyloid Imaging Against the Neuritic Plaque Component of Cerad and the Current (2012) NIA-AA Recommendations for the Neuropathologic Diagnosis of Alzheimer\u27s Disease

Introduction Performance of the amyloid tracer [18F]flutemetamol was evaluated against three pathology standard of truth (SoT) measures including neuritic plaques (CERAD €œoriginal€ and €œmodified€ and the amyloid component of the 2012 NIA-AA guidelines). Methods After [18F]flutemetamol imaging, 106 end-of-life patients who died underwent postmortem brain examination for amyloid plaque load. Blinded positron emission tomography scan interpretations by five independent electronically trained readers were compared with pathology measures. Results By SoT, sensitivity and specificity of majority image interpretations were, respectively, 91.9% and 87.5% with €œoriginal CERAD,€ 90.8% and 90.0% with €œmodified CERAD,€ and 85.7% and 100% with the 2012 NIA-AA criteria. Discussion The high accuracy of either CERAD criteria suggests that [18F]flutemetamol predominantly reflects neuritic amyloid plaque density. However, the use of CERAD criteria as the SoT can result in some false-positive results because of the presence of diffuse plaques, which are accounted for when the positron emission tomography read is compared with the 2012 NIA-AA criteria

Performance of [18F]flutemetamol amyloid imaging against the neuritic plaque component of CERAD and the current (2012) NIA‐AA recommendations for the neuropathologic diagnosis of Alzheimer’s disease

IntroductionPerformance of the amyloid tracer [18F]flutemetamol was evaluated against three pathology standard of truth (SoT) measures including neuritic plaques (CERAD “original” and “modified” and the amyloid component of the 2012 NIA‐AA guidelines).MethodsAfter [18F]flutemetamol imaging, 106 end‐of‐life patients who died underwent postmortem brain examination for amyloid plaque load. Blinded positron emission tomography scan interpretations by five independent electronically trained readers were compared with pathology measures.ResultsBy SoT, sensitivity and specificity of majority image interpretations were, respectively, 91.9% and 87.5% with “original CERAD,” 90.8% and 90.0% with “modified CERAD,” and 85.7% and 100% with the 2012 NIA‐AA criteria.DiscussionThe high accuracy of either CERAD criteria suggests that [18F]flutemetamol predominantly reflects neuritic amyloid plaque density. However, the use of CERAD criteria as the SoT can result in some false‐positive results because of the presence of diffuse plaques, which are accounted for when the positron emission tomography read is compared with the 2012 NIA‐AA criteria.HighlightsDetermination of the accuracy of [18F]flutemetamol image read against Aβ at autopsy.High sensitivity and specificity to 3 neuropathologic criteria as Standards of Truth.Images are 100% specific when the SoT reflects both neuritic and diffuse plaques.This study has the largest autopsy validation cohort for Aβ PET tracers to date.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152734/1/dad2jdadm201706001.pd